|
| 1 | +====================== |
| 2 | +Load balancer resizing |
| 3 | +====================== |
| 4 | +Link to blueprint: https://blueprints.launchpad.net/octavia/+spec/octavia-resize-loadbalancer |
| 5 | + |
| 6 | +This spec's goal is to describe the functionality of resizing of load |
| 7 | +balancers. The main aim of this new feature is to enable you to change the |
| 8 | +flavor directly from the API. |
| 9 | + |
| 10 | +Problem description |
| 11 | +=================== |
| 12 | +Today's users can't easily change the flavor. They have to recreate their load |
| 13 | +balancer with the new flavor and migrate their configurations such as |
| 14 | +l7 rules, listeners, etc. |
| 15 | +This can be very tedious for a user who wants to quickly resize his load |
| 16 | +balancer. It can be especially complicated to script. |
| 17 | + |
| 18 | +Proposed change |
| 19 | +=============== |
| 20 | +The proposed change would be to add an endpoint to allow load balancer |
| 21 | +resizing. It would also be easy to cancel a resize in progress and return |
| 22 | +to the previous flavor. |
| 23 | + |
| 24 | +To achieve this, the endpoint will launch a workflow to initiate a failover |
| 25 | +with the new flavor ID. This will involve patching the `get_failover_LB_flow` |
| 26 | +to add the `flavorId` parameter. At the end of the workflow the `flavor_id` |
| 27 | +will be updated in the `loadbalancer` table. |
| 28 | + |
| 29 | +A check will be added before the start of the failover to prevent migration |
| 30 | +to a flavor profile topology different from the original one. A user cannot |
| 31 | +migrate from a flavorprofile standalone to active/passive. |
| 32 | + |
| 33 | +If a problem occurs during resizing, the load balancer status will be set |
| 34 | +to ERROR. The flavor will remain the same in database, allowing the user |
| 35 | +to perform a failover or retry the same call. |
| 36 | + |
| 37 | +Alternatives |
| 38 | +------------ |
| 39 | + * Rebuild the vm of the loadbalancer with the new flavor compute. |
| 40 | + * Use the "backup" and "restore". |
| 41 | + |
| 42 | + |
| 43 | +Data model impact |
| 44 | +----------------- |
| 45 | +None |
| 46 | + |
| 47 | + |
| 48 | +REST API impact |
| 49 | +--------------- |
| 50 | +Add one endpoint in `/v2.0/lbaas/loadbalancers`. |
| 51 | + |
| 52 | +To run this endpoint, the user must have the role `load-balancer:write"`. |
| 53 | + |
| 54 | +Start a resize of a load balancer:: |
| 55 | + |
| 56 | + PUT /v2.0/lbaas/loadbalancers/{loadbalancer_id}/resize |
| 57 | + |
| 58 | + { |
| 59 | + "new_flavor_id": "6d425a5e-429f-4848-b240-ab31c6d211e4" |
| 60 | + } |
| 61 | + |
| 62 | +.. list-table:: Response code |
| 63 | + :widths: 15 50 |
| 64 | + :header-rows: 1 |
| 65 | + |
| 66 | + * - Code |
| 67 | + - Description |
| 68 | + * - 202 Accepted |
| 69 | + - Resize starting |
| 70 | + * - 400 Bad request |
| 71 | + - Resize object is invalid |
| 72 | + * - 401 Unauthorized |
| 73 | + - X-Auth-Token is invalid |
| 74 | + * - 403 Forbidden |
| 75 | + - X-Auth-Token is valid, but the associated project does not have |
| 76 | + the appropriate role/scope |
| 77 | + * - 404 Not Found |
| 78 | + - Load balancer not found |
| 79 | + |
| 80 | +Security impact |
| 81 | +--------------- |
| 82 | +None |
| 83 | + |
| 84 | +Notifications impact |
| 85 | +-------------------- |
| 86 | +Add a notification to announce a loadbalancer resize. |
| 87 | + |
| 88 | +Other end user impact |
| 89 | +--------------------- |
| 90 | +Add one command to launch resize in CLI client. |
| 91 | + |
| 92 | +Start a resize: openstack loadbalancer resize \ |
| 93 | + --flavor <flavor-id|flavor-name> \ |
| 94 | + <lb-id|lb-name> |
| 95 | + |
| 96 | +Add functions to resize in the `openstacksdk`. |
| 97 | + |
| 98 | +Performance Impact |
| 99 | +------------------ |
| 100 | +None |
| 101 | + |
| 102 | + |
| 103 | +Other deployer impact |
| 104 | +--------------------- |
| 105 | +None |
| 106 | + |
| 107 | + |
| 108 | +Developer impact |
| 109 | +---------------- |
| 110 | +None |
| 111 | + |
| 112 | + |
| 113 | +Implementation |
| 114 | +============== |
| 115 | + |
| 116 | +Assignee(s) |
| 117 | +----------- |
| 118 | +TBD |
| 119 | + |
| 120 | +Work Items |
| 121 | +---------- |
| 122 | + - Create endpoints |
| 123 | + - Patch the `get_failover_LB_flow` to add `flavorId` parameter. |
| 124 | + - Add unit tests |
| 125 | + - Add API functional tests |
| 126 | + - Add tempest tests |
| 127 | + - Update Octavia CLI and OpenstackSDK |
| 128 | + - Write Documentation |
| 129 | + |
| 130 | +Dependencies |
| 131 | +============ |
| 132 | +None |
| 133 | + |
| 134 | +Testing |
| 135 | +======= |
| 136 | +Tempest tests should be added for testing this new feature: |
| 137 | + - Create a loadbalancer |
| 138 | + - Try to resize |
| 139 | + |
| 140 | +Documentation Impact |
| 141 | +==================== |
| 142 | + - A user guide to explain how that works. |
| 143 | + - Add a note on the fact that some flavor changes can cause data plane |
| 144 | + downtime. Similarly, going from a newer image tag to an older one may |
| 145 | + cause failures or features to be disabled. |
| 146 | + |
| 147 | +References |
| 148 | +========== |
| 149 | +None |
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